WO2011077641A1

WO2011077641A1 - Epitaxial growing apparatus and method for manufacturing epitaxial growing apparatus

Info

Publication number: WO2011077641A1
Application number: PCT/JP2010/006902
Authority: WO
Inventors: 香蔵横田; 理大西; 周作杉山
Original assignee: 信越半導体株式会社
Priority date: 2009-12-24
Filing date: 2010-11-26
Publication date: 2011-06-30
Also published as: JP2011134871A; TW201137941A

Abstract

Disclosed is an epitaxial growing apparatus, wherein a gas supply means has: a perpendicular gas channel, which is connected to a gas supply source, and which has a gas flowing in the perpendicular direction; and a horizontal gas channel, which is connected to the downstream end portion of the perpendicular gas channel, and which supplies the gas to a substrate placed on a susceptor by jetting, in the horizontal direction, the gas supplied from the perpendicular gas channel. The perpendicular gas channel is a tree-like channel that is branched into a plurality of channels in the downstream. Thus, at the time of performing epitaxial growing on the substrate, nonuniformity of the flow speed of the raw material gas thus supplied can be effectively suppressed within the substrate surface, and a high quality epitaxial layer can be formed. A method for manufacturing the epitaxial growing apparatus is also disclosed.

Description

Epitaxial growth apparatus and manufacturing method of epitaxial growth apparatus

The present invention relates to an epitaxial growth apparatus for epitaxially growing a single crystal thin film on a substrate.

The semiconductor device manufacturing process includes a process of epitaxially growing a thin film on a semiconductor substrate. A schematic view of such a conventional epitaxial growth apparatus used for epitaxial growth is shown in FIG. In the epitaxial growth process using the epitaxial growth apparatus 104 shown in FIG. 5, the reactive gas 105 from the gas supply source 106 is applied to the substrate W placed on the susceptor 109 by the gas supply means 102 in the chamber 101 in which the outside air is shut off. A gas phase reaction is caused on the substrate W by the supplied source gas 105 to epitaxially grow a thin film, and then the source gas 105 is discharged out of the chamber 101 by the gas discharge means 103.

Epitaxial growth using such a device is used to increase the breakdown voltage of a bipolar device in the manufacturing process of a semiconductor device. When a megabit memory is also manufactured in the device, a soft error or latch-up due to alpha rays is used. It is a necessary technology to prevent this.

For example, when an epitaxial wafer is produced using such an epitaxial growth apparatus, it is important to reduce the velocity unevenness of the source gas on the substrate surface in order to deposit the epitaxial layer smoothly. However, since the diameter of the substrate is currently increased to 300 mm and is processed in a single wafer type, it is very difficult to form a flow having a wide range and no speed unevenness. Therefore, the thickness distribution of the epitaxial layer of the epitaxial wafer is often formed with unevenness corresponding to the flow of the source gas.

In order to solve such a problem, there is an apparatus in which the gas supply means 102 is made into a tree-like gas flow path that branches into a plurality in the horizontal direction in the apparatus 104 as shown in FIG. FIG. 6 shows a schematic view from the upper surface of the gas supply means 102 having a tree-like gas flow path through which gas flows in the horizontal direction. In such an apparatus, since the flow rates of the gas 105 ejected from a plurality of gas ejection ports connected to one gas supply source are the same, the flow velocity distribution in the substrate W plane of the supplied gas 105 is made uniform. And the thickness distribution of the epitaxial layer is improved.

As an apparatus having such a gas supply means, for example, as shown in Patent Document 1, an apparatus having a gas supply means of a laminated body in which a groove that forms a gas flow path is formed on a strip and bonded together by bolts or the like Is disclosed.

Special table 2008-516084

However, even with such gas supply means having a tree-like gas flow path that branches in the horizontal direction, the unevenness of the gas flow rate on the substrate cannot be sufficiently suppressed, and the thickness distribution of the epitaxial layer is sufficient. It was not possible to improve.
Further, as a problem in producing such a tree-like complicated gas flow path, when the inner surface of the gas flow path is electrolytically polished, polishing unevenness occurs, and gas is supplied to such a gas flow path. When flowing, there is a problem that particles or the like are generated on the surface of the epitaxial layer to be grown due to dust generation from a portion where polishing is not sufficient. In addition, even if the electropolishing can be carried out satisfactorily in an apparatus such as Patent Document 1, it is weak against temperature changes, and moreover, a gap is likely to occur in the gas flow path, because the band plate is joined by a bolt or clamp Contamination and dust generation problems may occur due to air contamination.

The present invention has been made in view of the above-mentioned problems, and when epitaxially growing on a substrate, it is possible to effectively suppress gas flow rate unevenness in a substrate surface of a supplied source gas, and a high-quality epitaxial layer It is an object of the present invention to provide an epitaxial growth apparatus and a method for manufacturing the same.

In order to achieve the above object, the present invention provides at least a chamber in which a susceptor on which a substrate to be epitaxially grown is placed, and a substrate placed on the susceptor in the chamber from a gas supply source. An epitaxial growth apparatus having a gas supply means for supplying a gas and a gas discharge means for discharging the supplied gas to the outside of the chamber, wherein the gas supply means is connected to at least the gas supply source and is vertical. A vertical gas flow path through which gas flows in a direction, and a downstream end of the vertical gas flow path, and the gas from the vertical gas flow path is ejected in a horizontal direction to the substrate placed on the susceptor. A vertical gas flow path is a tree-shaped flow path that branches into a plurality of flow paths toward the downstream side. To provide an epitaxial growth apparatus.

As described above, in the case of a tree-like vertical gas flow path, it is easy to uniformly flow the gas from the gas supply source to the branched flow paths. In the case of such a gas supply means of the epitaxial growth apparatus, the gas flowing in the vertical direction hits the connection portion with the horizontal gas flow path, so that the once dispersed gas flow is constant toward the gas outlet. Since the gas is then ejected in the horizontal direction, the gas flow rate unevenness in the substrate surface can be suppressed, and the gas can flow uniformly. Further, by arranging the tree-like gas flow paths vertically to form vertical gas flow paths, the gas flow paths can be branched into a sufficient number without increasing the apparatus width.

At this time, it is preferable that the vertical gas flow path is one in which gas flows from above to below.
With such a vertical gas flow path, the gas flow velocity distribution in the substrate surface to be processed can be made more uniform.

At this time, it is preferable that an outer corner surface of a connection portion between the horizontal gas flow path and the downstream end of the vertical gas flow path has an R shape.
If the outer corner surface has an R shape, the flowing gas is prevented from hitting the outer corner surface and backflowing, and the gas can be ejected in a more uniform flow.

At this time, it is preferable that the gas supply means has a plurality of the tree-like vertical gas flow paths in parallel.
If it is such a gas supply means, it will become an apparatus which can flow two or more kinds of gases efficiently and uniformly.

At this time, it is preferable that the inner surface of the vertical gas channel and / or the horizontal gas channel is electrolytically polished.
If it is such, it will become an apparatus which can prevent the dust generation from a gas flow path and can form a favorable epitaxial layer without a particle.

At this time, it is preferable that the gas supply means is diffusion bonded.
With such a gas supply means, there is no gas leakage, and the apparatus can perform epitaxial growth in which contamination due to air mixing or the like and generation of particles are prevented.

Further, the present invention provides at least a chamber in which a susceptor on which a substrate to be epitaxially grown is placed, and a gas supply for supplying gas from a gas supply source to the substrate placed on the susceptor in the chamber. A method of manufacturing an epitaxial growth apparatus having means and gas discharge means for discharging the supplied gas out of the chamber, wherein at least grooves and / or holes serving as gas flow paths are formed in the strip. A step of electropolishing the surface of the band plate in which the groove and / or the hole are formed, and bonding the band plates by performing diffusion bonding by superimposing the electropolished band plate on another band plate Forming a gas flow path, and at least a vertical gas flow path connected to the gas supply source and through which gas flows in a vertical direction, and an end portion downstream of the vertical gas flow path And a horizontal gas flow path for blowing gas from the vertical gas flow path in a horizontal direction and supplying gas to a substrate placed on the susceptor, and the vertical gas flow path is directed downstream. An epitaxial growth apparatus manufacturing method is provided that manufactures the gas supply means that is a tree-shaped flow path that branches into a plurality of flow paths.

By forming grooves and / or holes that serve as gas flow paths in the band plate and electrolytically polishing the grooves and / or holes, it is possible to perform good polishing without uneven polishing. Then, a gas flow path free from gas leakage or air mixing can be produced by stacking the electropolished band plate and another band plate and performing diffusion bonding to form a gas flow path. By manufacturing the gas supply means in such a process, even if the gas flow path has a complicated tree shape, the inner surface is satisfactorily electropolished and the gas flow path is free from air contamination. Can do. As a result, an epitaxial layer in which a uniform and in-plane gas can be flowed to the substrate to be processed by the tree-like vertical gas flow path and the horizontal gas flow path and the film thickness is uniform and contamination and particles are reduced. It is possible to reliably manufacture an epitaxial growth apparatus that can form the film.

As described above, according to the epitaxial growth apparatus of the present invention and the apparatus manufactured by the manufacturing method of the epitaxial growth apparatus of the present invention, gas can be flowed to the substrate to be epitaxially grown with a uniform gas flow velocity distribution, and the film thickness is uniform. Thus, an apparatus capable of forming a high-quality epitaxial layer can be provided.

It is the schematic which shows an example of the embodiment of the epitaxial growth apparatus of this invention. It is a schematic sectional drawing which shows the example of the cross-sectional shape of the gas supply means of the epitaxial growth apparatus of this invention. It is a flowchart explaining an example of the embodiment of the manufacturing method of the epitaxial growth apparatus of this invention. It is the schematic which shows partially the gas flow path of the gas supply means of the epitaxial growth apparatus of this invention. It is the schematic which shows an example of the conventional epitaxial growth apparatus. It is a schematic top view which shows an example of the gas flow path of the gas supply means of the conventional epitaxial growth apparatus. It is a division figure which divides and partially shows an example of the gas supply means of the epitaxial growth device of the present invention. It is a division figure which divides and shows partially another example of the gas supply means of the epitaxial growth device of the present invention. It is a graph which shows the number of particles of the epitaxial layer grown in the Example and the comparative example. It is a graph which shows the film thickness distribution of the epitaxial layer grown in the Example and the comparative example.

Hereinafter, the present invention will be described in detail as an example of an embodiment with reference to the drawings, but the present invention is not limited thereto.
FIG. 1 is a schematic view showing an example of an embodiment of an epitaxial growth apparatus of the present invention. FIG. 2 is a schematic sectional view showing an example of the sectional shape of the gas supply means of the epitaxial growth apparatus of the present invention. FIG. 4 is a schematic view showing a gas flow path with a solid line and other portions with a broken line in the gas supply means of the epitaxial growth apparatus of the present invention.

First, the epitaxial growth apparatus 14 of the present invention shown in FIG. 1 has a chamber 11 in which a susceptor 19 on which a substrate W to be epitaxially grown is placed, and a substrate W placed on the susceptor 19 in the chamber 11. Gas supply means 12 for supplying the gas 15 from the supply source 16 and gas discharge means 13 for discharging the supplied gas 15 out of the chamber 11 are provided.

In addition, the epitaxial growth apparatus 14 of the present invention may appropriately include a susceptor rotation mechanism 23 for rotating the susceptor 19, a lamp heating apparatus (not shown) for heating the substrate W, and the like.
The susceptor rotating mechanism 23 is for rotating the substrate W by rotating the susceptor 19 so that epitaxial growth is performed uniformly in the substrate surface.

The gas supply means 12 of the present invention is connected to a gas supply source 16 as shown in FIGS. 1, 2, and 4, and a vertical gas flow path 18 through which gas flows in a vertical direction, and a downstream of the vertical gas flow path 18. And a horizontal gas flow path 17 for blowing the gas 15 from the vertical gas flow path 18 in the horizontal direction and supplying the gas 15 to the substrate W placed on the susceptor 19. The flow path 18 is a tree-shaped flow path that branches into a plurality of flow paths toward the downstream as shown in FIG.

If such a vertical gas flow path 18 is a tree-shaped flow path, the gas 15 can be made to flow uniformly within the substrate surface by easy gas flow rate control. The gas 15 flowing in the vertical direction in the vertical gas flow path 18 hits the outer corner surface when flowing into the horizontal gas flow path, so that the gas variation toward the ejection port is suppressed, and the flow is more uniform. Become. Thereby, since the gas 15 is jetted horizontally and uniformly, the gas flow rate unevenness in the surface of the substrate W to be processed can be suppressed, and the film thickness can be epitaxially grown uniformly. In addition, by using the vertical gas flow path 18 that flows in the vertical direction in the tree-shaped flow path, even if the flow path is branched into a large number, it is not necessary to increase the width of the apparatus for branching. Therefore, it is advantageous in terms of space.

At this time, the flow direction of the gas in the vertical gas flow path 18 may be a vertical direction, and is not particularly limited from above to below or from below to above, but from above to below as shown in FIGS. It is preferable that the gas flows.
By forming such an L-shaped channel that flows in the vertical gas channel 18 from the upper side to the lower side and hits the lower surface of the horizontal gas channel 17 and flows in the horizontal direction, an inverted L-shaped flow that flows from the lower side to the upper side is formed. Compared with the path, the gas flow velocity distribution in the substrate surface of the gas 15 to be ejected is more uniform.

In addition, as shown in FIGS. 1 and 2, if the outer corner surface of the connecting portion between the horizontal gas channel 17 and the downstream end of the vertical gas channel 18 is R-shaped, the gas that hits the outer corner surface Since the backflow can be prevented and the gas flow can be changed smoothly in the horizontal direction, the apparatus can realize a more optimal flow.

Further, as shown in FIGS. 2B and 2C, the gas supply means 12 preferably has a plurality of tree-like vertical gas flow paths 18 in parallel. FIG. 2B shows the case where gas 1 and gas 2 are mixed in the middle of the vertical gas flow path 18 and flow out to the horizontal gas flow path 17. FIG. It flows through the gas flow path 18 and is mixed for the first time in the horizontal gas flow path 17.
With such an apparatus 14, two or more kinds of gases or gases having different concentrations can be caused to flow through the plurality of vertical gas flow paths 18 to be uniformly mixed, and various mixing is possible.

Moreover, it is preferable that the inner surface of the vertical gas channel 18 and / or the horizontal gas channel 17 is electrolytically polished.
As long as it is electrolytically polished, no dust is generated even when the gas 15 flows inside, and generation of particles in the epitaxial layer to be grown can be prevented.

The gas supply means 12 is preferably diffusion bonded.
In this way, diffusion bonding is suitable for use in producing the gas supply means 12 having a complicatedly shaped gas flow path according to the present invention, since it can be bonded to a temperature change without any gap. is there.

In the apparatus 14 of the present invention, the horizontal gas flow path 17 is not particularly limited, and slits or the like that match the positions of the vertical gas flow paths 18 may be formed, as shown in FIG. Further, there may be no slit or the like and the flow path is not divided.

As a method for manufacturing such an epitaxial growth apparatus of the present invention, a method of manufacturing the epitaxial growth apparatus according to the present invention will be described below.
FIG. 3 is a flow diagram illustrating an example of an embodiment of a method for manufacturing an epitaxial growth apparatus of the present invention with a schematic front view and a schematic cross-sectional view.

First, in the manufacturing method of the present invention, as shown in FIGS. 3A and 3B, grooves and / or holes 20 and 21 serving as gas flow paths are formed in the strip plates 22a and 22b. For example, in the band plate 22a shown in FIG. 3A, grooves 20 to be the vertical gas flow paths 18 are formed in a tree shape as shown in the front view, and perpendicular to the band plate 22b shown in FIG. 3B. A groove 20 to be the gas flow path 18 is formed in the same manner as the band plate 22a, and a hole 21 to be the horizontal gas flow path 17 is formed. As a method of forming the grooves and / or holes 20 and 21, for example, the grooves and / or holes 20 and 21 can be formed by cutting with an end mill.
At this time, in FIGS. 3A and 3B, the grooves and / or the

holes

20 and 21 are formed in both of the band plates 22a and 22b, but they may be formed only in one of the band plates.

Next, the surfaces of the strips 22a and 22b are electropolished. The method of electrolytic polishing is not particularly limited. For example, when a strip that is polished in an electrolytic solution is connected positively to flow electricity, minute projections on the surface are preferentially dissolved to obtain a bright surface. It is done.
As described above, according to the manufacturing method of the present invention, the strips 22a and 22b in which the grooves and / or the

holes

20 and 21 are formed are electropolished, so that polishing unevenness is less likely to occur than when the tubular flow path is electropolished. In addition, a gas flow path having an inner surface that does not generate dust even when gas is allowed to flow.

Next, as shown in FIG. 3C, the strips 22a and 22b are overlapped and diffusion bonding is performed to join the strips 22a and 22b to each other so that the vertical gas flow path 18 and the horizontal gas flow path 17 are joined. Form.
The method of diffusion bonding is not particularly limited. For example, the overlapped strips 22a and 22b are joined by atomic movement between the strips 22a and 22b under high pressure and high pressure while being pressed in a vacuum state. By joining the strips 22a and 22b by such diffusion bonding, there is no gap, and it is possible to join strong against temperature changes. An apparatus capable of performing epitaxial growth without contamination or generation of particles can be manufactured.

Thereafter, as shown in FIG. 3 (d), a gas ejection port is formed through the horizontal gas flow path 17, and final surface processing is performed as shown in FIG. 3 (e). A pipe from the supply source 16 is welded to the connection portion to complete the gas supply means 12 of the present invention and attached to the epitaxial growth apparatus 14.
FIG. 7 shows a schematic view of the state of being divided at the joint surface of the gas supply means 12 of the epitaxial growth apparatus 14 of the present invention manufactured as described above.

In the above description, the method for manufacturing a gas supply means having a single-layer type vertical gas flow path has been described. However, regarding the manufacture of a gas supply means having a multi-layer vertical gas flow path having a plurality of vertical gas flow paths in parallel. For example, in the case of a two-layer type, gas supply means 12 as shown in FIGS. 2B, 2C, and 8 is formed by forming grooves or the like in three strips and performing diffusion bonding in the same manner as described above. Can be produced. FIG. 8 is a schematic view of the epitaxial growth apparatus 14 of the present invention, in which the gas supply means 12 having the two-layer type vertical gas flow path 18 is divided at the joint surface. Of course, if necessary, it may have three or more layers of vertical gas channels made of four or more strips.

According to the apparatus manufactured by the apparatus of the present invention and the manufacturing method of the present invention as described above, the gas can be flowed to the substrate to be epitaxially grown with the in-plane uniform gas flow rate distribution, the film thickness is uniform, and the quality is high. The epitaxial layer can be formed.

EXAMPLES Hereinafter, although an Example and a comparative example are shown and this invention is demonstrated more concretely, this invention is not limited to these.
Example 1
Epitaxial growth was performed on a silicon wafer having a diameter of 300 mm using the epitaxial growth apparatus of the present invention shown in FIGS. 1 and 4 manufactured by the manufacturing method of the present invention. An apparatus having 96 ports at the downstream end of the vertical gas channel of the gas supply means was used. The gas supply means is an L-shaped gas flow path as shown in FIGS. 1 and 4 in which the gas flows from the top to the bottom in the vertical gas flow path.
The epitaxial growth conditions were a reaction temperature of 1150 ° C., a hydrogen flow rate of 70 slm, a TCS (trichlorosilane) gas flow rate of 10 slm, and an epitaxial layer was grown to a film thickness of 5 μm.

(Example 2)
The apparatus was the same as in Example 1, except that the gas supply means was an inverted L-shaped gas flow path in which the gas flowed from below to above in the vertical gas flow path. The epitaxial growth conditions were the same as in Example 1.

(Comparative example)
Epitaxial growth was carried out on a silicon wafer having a diameter of 300 mm using an epitaxial growth apparatus having a tree-like horizontal gas flow path gas supply means shown in FIGS. An apparatus having 96 ports at the downstream end of the gas flow path of the gas supply means was used. Further, the gas supply means was formed by forming a groove serving as a gas flow path in the strip, electrolytic polishing, and then joining the strips with bolts and nuts.
The epitaxial growth conditions were the same as in Examples 1 and 2, and the epitaxial layer was grown to a thickness of 5 μm.

FIG. 9 shows the result of measuring the number of particles in the epitaxial layer formed in Example 1 and the comparative example, and FIG. 10 shows the result of measuring the film thickness distribution of the epitaxial layer.
As shown in FIG. 10, according to the apparatus of the present invention in Example 1, an epitaxial layer having a very uniform film thickness uniformity of 0.18% is formed, and gas channels having the same number of ports are formed. It can be seen that the film thickness uniformity is higher than that of the comparative example (film thickness uniformity = 1.20%). Further, as shown in FIG. 9, the number of particles was smaller in the apparatus according to the embodiment of the present invention. Regarding the effect of reducing the number of particles, it is considered that the comparative example was joined with bolts and nuts as in the prior art, while the apparatus of the present invention joined the strips by diffusion joining.
Further, in Example 2, the number of particles measured in the same manner was about the same as that in Example 1, but the film thickness uniformity was 0.28%, which is an improvement over the comparative example. It was slightly lower than. From this result, it can be seen that the uniformity of the thickness of the formed epitaxial layer is further improved when the gas supply means has an L-shaped gas flow path rather than an inverted L-shaped gas channel.

The present invention is not limited to the above embodiment. The above-described embodiment is an exemplification, and the present invention has the same configuration as the technical idea described in the claims of the present invention. It is included in the technical scope of the invention.

Claims

At least a chamber in which a susceptor on which a substrate to be epitaxially grown is placed is installed, gas supply means for supplying a gas from a gas supply source to the substrate placed on the susceptor in the chamber, and the supply An epitaxial growth apparatus having gas exhaust means for exhausting the gas out of the chamber,
The gas supply means is connected to at least the gas supply source, and is connected to a vertical gas flow path through which gas flows in the vertical direction and a downstream end of the vertical gas flow path, and gas from the vertical gas flow path A horizontal gas flow path for supplying gas to a substrate placed on the susceptor by blowing out the gas horizontally, and the vertical gas flow path branches into a plurality of flow paths toward the downstream An epitaxial growth apparatus characterized by being a channel.
The epitaxial growth apparatus according to claim 1, wherein the vertical gas flow path is a gas flow from above to below.
3. The epitaxial growth apparatus according to claim 1, wherein an outer corner surface of a connection portion between the horizontal gas flow path and the downstream end of the vertical gas flow path has an R shape.
4. The epitaxial growth apparatus according to claim 1, wherein the gas supply unit includes a plurality of the tree-like vertical gas flow paths in parallel. 5.
The epitaxial growth apparatus according to any one of claims 1 to 4, wherein an inner surface of the vertical gas flow path and / or the horizontal gas flow path is subjected to electrolytic polishing.
The epitaxial growth apparatus according to any one of claims 1 to 5, wherein the gas supply means is diffusion bonded.
At least a chamber in which a susceptor on which a substrate to be epitaxially grown is placed is installed, gas supply means for supplying a gas from a gas supply source to the substrate placed on the susceptor in the chamber, and the supply A method of manufacturing an epitaxial growth apparatus having a gas discharge means for discharging the gas out of the chamber, comprising:
Forming a groove and / or hole to be a gas flow path in the band plate;
Electropolishing the surface of the strip in which the grooves and / or holes are formed;
Forming a gas flow path by joining the strips together by performing diffusion bonding by superimposing the electropolished strip with other strips,
At least connected to the gas supply source, connected to a vertical gas flow path through which gas flows in the vertical direction, and a downstream end of the vertical gas flow path, and ejects gas from the vertical gas flow path in the horizontal direction. A horizontal gas flow path for supplying gas to the substrate placed on the susceptor, and the vertical gas flow path is a tree-shaped flow path that branches into a plurality of flow paths toward the downstream. A method for manufacturing an epitaxial growth apparatus, wherein the gas supply means is manufactured.